Fingerprint sensing and matching is a reliable and widely used technique for personal identification or verification. In particular, a common approach to fingerprint identification involves scanning a sample fingerprint or an image thereof and storing the image and/or unique characteristics of the fingerprint image. The characteristics of a sample fingerprint may be compared to information for reference fingerprints already in a database to determine proper identification of a person, such as for verification purposes.
A particularly advantageous approach to fingerprint sensing is disclosed in U.S. Pat. No. 5,953,441 to Setlak and assigned to the assignee of the present invention, the entire contents of which are herein incorporated by reference. The fingerprint sensor is an integrated circuit sensor that drives the user's finger with an electric field signal and senses the electric field with an array of electric field sensing pixels on the integrated circuit substrate.
U.S. Pat. No. 6,289,114 to Mainguet, which is assigned to the assignee of the present invention and is incorporated in its entirety by reference, discloses a fingerprint sensor that includes a finger sensing integrated circuit (IC). The finger sensing IC includes a layer of piezoelectric or pyroelectric material placed between upper and lower electrodes to provide electric signals representative of an image of the ridges and valleys of the fingerprint.
A particularly advantageous approach to multi-biometric fingerprint sensing is disclosed in U.S. Pat. No. 7,361,919 to Setlak, which is assigned to the assignee of the present invention and is incorporated in its entirety by reference. The Setlak patent discloses a multi-biometric finger sensor sensing different biometric characteristics of a user's finger that have different matching selectivities.
A fingerprint sensor may be particularly advantageous for verification and/or authentication in an electronic device, and more particularly, a portable device, for example. Such a fingerprint sensor may be carried by the housing of a portable electronic device, for example, and may be sized to sense a fingerprint from a single-finger. Other fingerprint sensors, for example, a multi-function smart sensor expands touch-based functionality of touchscreen and QWERTY smartphones with a reduced impact on sensor performance or durability. Thus, a fingerprint sensor may be particularly advantageous for providing more convenient access to the electronic device without a password, for example, and, more particularly, without having to type the password, which is often time consuming.
U.S. Patent Application Publication No. 2011/0175703 to Benkley, III discloses an electronic imager using an impedance sensor grid array mounted on or about a switch. More particularly, Benkley, III discloses a switch being incorporated into a sensor assembly that allows integration of sensor operations, such as, fingerprint sensor operations. A fingerprint sensor can be used for authentication while being used together with a power switch or navigation selection switch. The authentication may be used to access the device entirely or access different levels of information.
U.S. Pat. No. 8,006,099 to Aoyama et al. discloses a portable terminal device, for example, a phone that includes a fingerprint sensor. An authentication unit may cooperate with the fingerprint sensor to unlock the device based upon a fingerprint authentication, a personal identification number (PIN) code, or a combination of a fingerprint authentication and the PIN code.
U.S. Pat. No. 8,046,721 to Chaudhri et al. discloses unlocking of a device by performing gestures on an unlocking image. More particularly, a device with a touch-sensitive display is unlocked if contact with the display corresponds to a predefined gesture for the unlocking device.